Can there be a problem of too much headspace on mead? I've started converting to bulk aging and running into a car boy challenge which has me being creative with fermenting and aging vessels. I fermented a 3 gal batch in a 5 gal carboy; never noticed a problem through the fermentation but received a surprise when I racked it yesterday and the SG was 1.000. I'm having trouble believing the alcohol disappeared or is hiding. I did notice two variances from other fermentations; one, the CO2 would escape in "gulps" rather than the "pop, pop, pop" of individual bubbles. Second, when I was preparing to rack I noticed the liquid level was approximately 1/2 inch below the "dried foam line" in the carboy.
It was actively fermenting for over a month around 68 deg F and had finally slowed significantly and cleared beautifully.There was still plenty of co2 in solution with it flashing to gas when I bumped the carboy, as it ran through the tubing and in racking carboy. It also "fizzed" well when I added K-met. The cylinder I use for the hydrometer had bubbles hanging on the inside walls and releasing to where it almost looked like a sparkling mead. The SG is telling me it's water and tasting isn't contradicting it. It doesn't taste bad, more along the lines of a weak tea with no alcohol (it's a sassafras mean).
Mead Is very susceptible to Oxidation This is why we rack mead with no or little splash, Even though the offgassing of CO2 can shield the mead, when the mead goes still the extra surface area can expose the mead to Oxygen. So we should always try to keep the carboy filled to the neck. Even if toping off with a finished mead, or Distilled water is required.
A hydrometer measures the density of a liquid. It is calibrated for straight water at 60F Alcohol is thinner than water so a hydrometer will not measure alcohol by volume. once the sugar is converted to alcohol we cannot read it. This is why it is so important to take SG readings at the beginning of the ferment. If one cannot taste the alcohol in a dry mead they are either an extremely seasoned drinker, or the ABV is low.
We figured out the problem and it was my application of the recipe, to correct the first batch I fermented a couple of gal high SG and added it to the 3 gal batch. The high SG sassafras was really good and I'm making another couple of gal this week.